Machine-readable code

ABSTRACT

Technology for generating, reading, and using machine-readable codes is disclosed. There is a method, performed by an image capture device, for reading and using the codes. The method includes obtaining an image, identifying an area in the image having a machine-readable code. The method also includes, within the image area, finding a predefined start marker defining a start point and a predefined stop marker defining a stop point, an axis being defined there between. A plurality of axis points can be defined along the axis. For each axis point, a first distance within the image area to a mark is determined. The distance can be measured from the axis point in a first direction which is orthogonal to the axis. The first distances can be converted to a binary code using Gray code such that each first distance encodes at least one bit of data in the code.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No.16207062.7, titled MACHINE READABLE CODE, filed on Dec. 28, 2016.

BACKGROUND

Optical machine-readable codes have long been used. Examples includeone-dimensional barcodes, such as Universal Product Code (UPC, e.g.,UPC-A) barcodes, which have information encoded in the width and spacingof lines, and Intelligent Mail (IM) barcodes, which have informationencoded in bars that extend up and/or down. Examples of opticalmachine-readable codes also include two-dimensional bar codes, such asQuick Response (QR) codes, which encode information in a regular grid ofblack and white pixels with visible tracking markers. Two-dimensionalcodes may also use rectangles, dots, hexagons and other geometricpatterns in two dimensions to represent data. Modern two-dimensional barcodes, that are associated with a specific company, are often called“scannables”. Tracking markers are necessary in the existing codes toalign the capture image to a grid for reading the code. Such trackingmarkers can disrupt the appearance of the scannable.

SUMMARY

In general terms this application is directed to generating, reading,and using machine-readable codes. In one possible configuration and bynon-limiting example, there is a method of reading an opticalmachine-readable code performed by an image capture device, the methodincluding: capturing a digital image with an image sensor of the imagecapture device; identifying an image area in the captured digital image,the image area comprising the machine-readable code; within the imagearea, finding a predefined optical start marker defining a start pointand finding a predefined optical stop marker defining a stop point,wherein an axis is defined between the start point and the stop point;defining a plurality of axis points along the axis; for each axis point,determining a first distance within the image area to an optical mark,measured from the axis point in a first direction which is orthogonal tothe axis; and translating the first distances to a binary code usingGray code, each first distance encoding at least three bits of thebinary code.

In another possible configuration, there is a non-transitory computerreadable medium comprising instructions executable by a processor toperform a method. The method can include capturing a digital image usingan image sensor of the image capture device; identifying an image areain the captured digital image, the image area comprising themachine-readable code; within the image area, finding a predefinedoptical start marker defining a start point and find a predefinedoptical stop marker defining a stop point, an axis being defined betweenthe start point and the stop point; defining a plurality of axis pointsalong the axis; for each axis point, determining a first distance withinthe image area to an optical mark, measured from the axis point in afirst direction which is orthogonal to the axis; and translating thefirst distances to a code.

In yet another possible configuration, there is a method for generatingan optical machine-readable code, the method comprising: obtaining data;translating the data into first distances within an image area, each ofthe first distances being measured from an axis point on an axis in theimage area, in a first direction which is orthogonal to the axis;forming a mark at the end of each of the first distances in the imagearea; forming a start marker at a first end of the axis, wherein thestart marker defines a start point; forming a stop marker at a secondend of the axis, wherein the stop marker defines a stop point; andproviding the image area.

According to another aspect of the present disclosure, there is provideda computer program product comprising computer-executable components forcausing an image capture device to perform an embodiment of a method ofthe present disclosure when the computer-executable components are runon processing circuitry of the image capture device.

According to another aspect of the present disclosure, there is providedan image capture device for reading an optical machine-readable code.The image capture device includes processing circuitry, and storagestoring instructions executable by the processing circuitry whereby theimage capture device captures an image using an image sensor of theimage capture device. The image capture device is also configured toidentify an image area in the captured digital image, the image areahaving the machine-readable code. The image capture device is alsoconfigured to, within the image area, find a predefined optical startmarker defining a start point and find a predefined optical stop markerdefining a stop point, an axis being defined between the start point andthe stop point. The image capture device is also configured to define aplurality of axis points along the axis. The image capture device isalso configured to, for each axis point, determine a first distancewithin the image area to an optical mark, measured from the axis pointin a first direction which is orthogonal to the axis. The image capturedevice is also configured to translate the first distances to a binarycode using Gray code, each first distance encoding at least three bitsof the binary code. The image capture device may thus be arranged toperform embodiments of the method of reading an optical machine-readablecode in accordance with the present disclosure. The image capture devicemay, for example, be a smartphone having a digital camera.

According to another aspect of the present disclosure, there is provideda method performed by a code generator. The method includes obtaining abinary code. The method also includes translating the binary code, usingGray code, into first distances within an image area, each of the firstdistances being measured from an axis point on an axis in the imagearea, in a first direction which is orthogonal to the axis. The methodalso includes forming an optical mark at the end of each of the firstdistances in the image area. The method also includes, at each end ofthe axis, forming an optical start marker and stop marker, respectively,defining a start point and a stop point, respectively, of the axiswithin the image area. The method also includes compositing the imagearea in an image. The method also includes presenting the digital imageon an optical display whereby the optical marks form an opticalmachine-readable code in the image area in the digital image.

According to another aspect of the present disclosure, there is provideda computer program product having computer-executable components forcausing a code generator to perform an embodiment of a method of thepresent disclosure when the computer-executable components are run onprocessing circuitry comprised in the code generator.

According to another aspect of the present disclosure, there is provideda code generator having processing circuitry, and storage storinginstructions executable by the processing circuitry whereby the codegenerator is configured to obtain a binary code. The code generator isalso operative to translate the binary code, using Gray code, into firstdistances within an image area, each of the first distances beingmeasured from an axis point on an axis in the image area, in a firstdirection which is orthogonal to the axis. The code generator is alsoconfigured to form an optical mark at the end of each of the firstdistances in the image area. The code generator is also configured to,at each end of the axis, form an optical start marker and stop marker,respectively, defining a start point and a stop point, respectively, ofthe axis within the image area. The code generator is also configured tocomposite the image area in a digital image. The code generator is alsoconfigured to present the digital image on an optical display wherebythe optical marks form an optical machine-readable code in the imagearea in the digital image. The code generator may thus be arranged toperform embodiments of the method for generating a code in accordancewith the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic diagram of an example communication network systemwith which aspects of technologies disclosed herein may be used.

FIG. 2 is a schematic block diagram of an example image capture device.

FIG. 3 is a schematic block diagram of an example code generator.

FIG. 4 is a schematic illustration of an example computer programproduct.

FIG. 5 is a schematic illustration of an example a digital image.

FIG. 6A illustrates an example representation of an opticalmachine-readable code.

FIG. 6B illustrates an example representation of an opticalmachine-readable code.

FIG. 6C illustrates an example representation of an opticalmachine-readable code.

FIG. 6D illustrates an example representation of an opticalmachine-readable code.

FIG. 6E illustrates an example representation of an opticalmachine-readable code.

FIG. 7 illustrates an example process for identifying and preparingimages for deciding.

FIG. 8A illustrates an example of an image that can be obtained at animage capture device.

FIG. 8B illustrates another example of an image that can be obtained atan image capture device.

FIG. 8C illustrates an example deskewed image.

FIG. 8D illustrates another example deskewed image.

FIG. 9 illustrates an example process for analyzing a candidate code.

FIG. 10 illustrates an embodiment of an optical machine-readable code.

FIG. 11 illustrates an example of determining the error for a marker.

FIG. 12 illustrates an embodiment of processing of a binary codeobtained from an optical machine-readable code.

FIG. 13 illustrates an example process for a source to provide contentto an image capture device using an optical code.

FIG. 14 illustrates an example system in which a first device capturesan optical code from a second device to associate the second device withan account of a user at a server.

FIG. 15 illustrates an example process for associating a second devicewith an account of a user on a first device using an optical code.

DETAILED DESCRIPTION

Various embodiments will be described in detail with reference to thedrawings, wherein like reference numerals represent like parts andassemblies throughout the several views. Reference to variousembodiments does not limit the scope of the claims attached hereto.Additionally, any examples set forth in this specification are notintended to be limiting and merely set forth some of the many possibleembodiments for the appended claims.

Some embodiments according to the present disclosure provide analternative and, in some applications, more practical way of generating,presenting, reading, and interpreting an optical machine-readable code.The optical machine-readable code may be designed to convey, in itsvisual appearance, an association to streaming sound and music, withoutany disrupting tracking markers. The tracking markers (e.g., start,stop, and reference markers) may be associated with the code in a mannerto further the association to streaming sound and music. By generatingthe optical machine-readable code such that distances from an axisencode the data held by the optical machine-readable code (e.g., binarycode), a more practical alternative to conventional barcodes may beobtained, depending on the application. The optical machine-readablecode may, for example, work better (e.g., better fit or blend) with thedigital image as a whole.

It is to be noted that any feature of any of the aspects disclosedherein may be applied to any other aspect herein, wherever appropriate.Likewise, any advantage of any of the aspects may apply to any of theother aspects. Other objectives, features and advantages of the enclosedembodiments will be apparent from the following detailed disclosure,from the attached dependent claims as well as from the drawings.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated. The use of “first”, “second”, andthe like for different features/components of the present disclosure areonly intended to distinguish the features/components from other similarfeatures/components and not to impart any order or hierarchy to thefeatures/components.

Embodiments will now be described more fully hereinafter with referenceto the accompanying drawings, in which certain embodiments are shown.However, other embodiments in many different forms are possible withinthe scope of the present disclosure. Rather, the following embodimentsare provided by way of example so that this disclosure will be thoroughand complete, and will fully convey the scope of the disclosure to thoseskilled in the art. Like numbers refer to like elements throughout thedescription.

FIG. 1 illustrates an embodiment of a communication network system 1with which aspects of technologies disclosed herein may be used. Thesystem 1 includes an image capture device 2, such as a wired or wirelessdevice (e.g., a radio device) having an image sensor for capturing animage. In some examples, the image capture device 2 may be any device oruser equipment (UE), whether mobile or stationary, enabled tocommunicate over a radio channel in a communication network system 1.For instance, the device 2 may, but need not, be limited to, a mobilephone, a smartphone, a media player, a camera, a tablet computer, alaptop, a personal computer (PC), or a consumer electronic device.Preferably, the image capture device 2 is a smartphone having a camerawith a digital image sensor. The figure illustrates a user 7 using theimage capture device 2.

Where the image capture device 2 is a radio device, it may be connectedto a network such as a Packet Data Network (PDN) 6 (e.g., the Internet)via any Radio Access Network (RAN) 8 (e.g., a Local Area Network (LAN)or a cellular network in accordance with a Third Generation PartnershipProject (3GPP) communication standard) having one or more base stations.

The image capture device 2 may be in the vicinity of an optical display4 (e.g., an LCD or AMOLED panel of a smartphone or tablet) that presentsan optical digital image. The device 2 can use its image sensor tocapture the optical digital image.

The optical display 4 can be included in or communicatively connected toa code generator 3 (e.g., via the PDN 6). The code generator 3 isconfigured to generate an optical machine-readable code for display inthe digital image on the optical display 4. The code generator 3 may,for example, be hosted by a service provider (SP) 5 having a server 9.

FIG. 2 illustrates an example embodiment of the image capture device 2(e.g., a smartphone). The image capture device 2 includes processingcircuitry 21 (e.g., a central processing unit). The processing circuitry21 can include one or more processing units in the form ofmicroprocessor(s). However, other suitable devices with computingcapabilities can make up the processing circuitry 21, such as anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), or a complex programmable logic device (CPLD). Theprocessing circuitry 21 can be configured to run one or several computerprogram(s) or software (SW) 25 (see also FIG. 4) stored in a storage 22of one or more storage unit(s) (e.g., memory). The software 25 caninclude, for example application software for a software application(app) 24 for making the image capture device 2 perform an embodiment ofa method of the present disclosure. The app 24 can be formed by theprocessing circuitry 21 running the application software. The storage 22can be regarded as a computer readable medium (see, e.g., computerreadable medium 42 of FIG. 4). The computer readable medium can include,for example, Random Access Memory (RAM), flash memory, other solid statememory, a hard disk, or combinations thereof. The computer readablemedium can include a non-transitory computer readable medium. Theprocessing circuitry 21 can be configured to store data in the storage22, as needed.

The image capture device 2 can also include an image sensor 27. Theimage sensor 27 is typically a portion of a camera 26 integrated in theimage capture device 2. The image sensor 27 may take various forms,including, for example, a semiconductor charge-coupled devices (CCD), oractive pixel sensors in complementary metal-oxide-semiconductor (CMOS),or N-type metal-oxide-semiconductor (NMOS, Live MOS) image sensor.Further, the image capture device 2 may include a communicationinterface 23 (e.g., a radio interface) for communication within thecommunication network system 1 (e.g., with the SP 5) such as with theserver 9 thereof.

FIG. 3 illustrates an embodiment of a code generator 3. The codegenerator 3 can include processing circuitry 31 (e.g., a centralprocessing unit). The processing circuitry 31 can include one or moreprocessing units in the form of microprocessors. However, other suitabledevices with computing capabilities can also be included in theprocessing circuitry 31 (e.g., an ASIC, FPGA, or CPLD). The processingcircuitry 31 can be configured to run one or more computer program(s) orsoftware (SW) (see also software 34 of FIG. 4) stored in a storage 32that may include one or more storage unit(s) (e.g., a memory). Thestorage units can be regarded as a computer readable medium 42 (see FIG.4) as discussed herein and may, for example, be in the form of RAM,flash memory, solid state memory, a hard disk, or combinations thereof.The storage can include a non-transitory computer readable medium. Theprocessing circuitry 31 can also be configured to store data in thestorage 32, as needed. The code generator 3 can also include acommunication interface 33 for communication within the communicationnetwork system 1, for example with the SP 5 (e.g., such as with theserver 9 thereof or with the optical display 4 which may or may not bepart of the code generator 3).

In an example the storage 32 includes instructions that, when executedby the processing circuitry 31, cause the generator 3 to create anoptical code decodable using one or more techniques disclosed herein. Inan example, the instructions cause the processing circuitry to obtain abinary code (e.g., a binary representation of content to be stored in anoptical code) to be encoded into an optical code. The instructions cancause the processor to translate the binary code, using Gray code, intofirst distances within an image area, each of the first distances beingmeasured from an axis point on an axis in the image area, in a firstdirection which is orthogonal to the axis. The instructions can alsocause the processing circuitry 31 to form an optical mark at the end ofeach of the first distances in the image area. The instructions can alsocause the processing circuitry 31 to, at each end of the axis, form anoptical start marker and stop marker, respectively, defining a startpoint and a stop point, respectively, of the axis within the image area.The instructions can also cause the processing circuitry 31 to compositethe image area in a digital image and provide digital image, such as onan optical display whereby the optical marks form an opticalmachine-readable code in the image area in the digital image. The codegenerator 3 may thus be arranged to perform embodiments of the methodfor generating a code in accordance with the present disclosure.

FIG. 4 illustrates an embodiment of a computer program product 40. Thecomputer program product 40 includes a computer readable (e.g.non-volatile and/or non-transitory) medium 42 having software/computerprogram 25 and/or 34 in the form of computer-executable components. Thecomputer program 25/34 can be configured to cause an image capturedevice 2 or code generator 3 (e.g., as discussed herein) to perform anembodiment of a method of the present disclosure. The computer programmay be run on the processing circuitry 21/31 of the image capture device2 or code generator 3 to cause it to perform the method. The computerprogram product 40 may, for example, be included in a storage unit ormemory 22/32 of the image capture device 2 or code generator 3 and maybe associated with the processing circuitry 21/31. Alternatively, thecomputer program product 40 may be, or be a part of, a separate (e.g.,mobile) storage medium, such as a computer readable disc (e.g., a CD orDVD), a hard disc, a hard drive, or a solid state storage medium (e.g.,a RAM or flash memory). Embodiments of the present disclosure can beconveniently implemented using one or more conventional general purposeor specialized digital computers, computing devices, machines, ormicroprocessors, including one or more processors, memory and/orcomputer readable storage media programmed according to the teachings ofthe present disclosure. Appropriate software coding can readily beprepared by skilled programmers based on the teachings of the presentdisclosure, as will be apparent to those skilled in the software art.

In some embodiments, a scannable code (herein called an “opticalmachine-readable code” or, simply, an “optical code”) may be generatedwith the information encoded in a representation. The representation maybe one that a user may associate with a soundwave. The association maybe strengthened by an animation lead in that shows the optical code as amoving soundwave.

FIG. 5 illustrates an example digital image 302 that includes an area102 and an image area 310. The area 102 may include an image withoverlaid text, graphics, and/or logotypes (e.g., album art). The imagearea 310 may contain a media company logotype 106 and an opticalmachine-readable code 108. The optical machine-readable code 108 caninclude a start marker 401, a stop marker 402, and a reference mark 406.

The optical machine-readable code 108 can be visually similar to (e.g.,be associated with) a soundwave. There are several possible ways to makethis association. Some examples are shown in FIG. 6A-E, which showoptical machine-readable code examples 202, 204, 206, 208, and 210 ashaving different possible representations that are visually similar to asoundwave. Example 202 includes a number of dots within columns (e.g.,rectangular regions). Example 204 includes bars. Example 206 includes asingle dot per column. Example 208 includes a single-line contour.Example 210 includes double-line contours.

An optical machine-readable code 108 may be decoded in a variety ofways. In some examples the decoding process can begin with preparing animage for decoding. FIG. 7 illustrates an example process 700 foridentifying and preparing images for decoding.

The process 700 can begin with operation 702, which involves obtainingan image. The image can be obtained in a variety of ways, such as bybeing captured by the camera 26 or selected from a library of photos.FIG. 8A illustrates an example of an image 302 that may be obtained. Ascan be seen, the object in the image 203 is skewed due to, for example,the image being taken non-orthogonally to the object in the image.

The process 700 can continue to operation 704, which involves processingthe obtained image. This processing can include manipulating the imageto make it easier to process in later steps. For example, the image canbe processed by converting it to grayscale, increasing or decreasingcontrast, increasing or decreasing brightness, and reducing noise, amongothers.

The process 700 can continue to operation 706, which involves performingedge detection. The image can be further processed by, for example,performing edge detection within the image. Edge detection can beperformed in a variety of ways, such as by using, for example, edgedetection algorithms from a computer vision library, such as OPENCV.

The process 700 can continue to operation 708, which involvesidentifying shapes in the image. For example, the shapes can bequadrilaterals. Edges that cross in a pattern that may indicate aquadrilateral (e.g., a rectangle viewed in perspective). Shapes ofinterest are selected for closer examination (e.g., selected ascandidates for parsing). In the example image illustrated in FIG. 8b ,there are three quadrilaterals: quadrilateral 304, quadrilateral 306,and the quadrilateral formed by the outer boundary of the combination ofquadrilateral 304 and quadrilateral 306. Each quadrilateral is acandidate area that may contain an optical machine-readable code.

The operation 708 can further involve identifying quadrilaterals likelyto contain an optical machine-readable code. For example, where a code(e.g., a code for which the method is configured to decode) has anoverall elongate shape (e.g., as seen in the codes in FIGS. 6A-E),identifying likely candidates involves identifying quadrilaterals havingtwo sides much longer than the other two (e.g., having an elongateshape, such as quadrilateral 306 in FIG. 8b ). If so, the likelycandidate can be used for processing.

The operation 708 can further involve generating candidate rotatedshapes. For example, the same code may yield different encoded data(e.g., messages) depending on how it is rotated. Generating candidaterotations may be based on the configuration of the code and the shape.For example, where both the shape and the code are elongate, tworotations may be used: a first image where one elongate side is aboveanother elongate side and another image generated by rotating the firstimage 180 degrees. If the sides are of similar length, then fourrotations are tested. For instance, where the shape is a square, therotations may be 90 degrees to each other where each end of the shape ison top.

The process 700 can further involve straightening or otherwise deskewingthe image or a portion thereof. For example, where the image is based ona photo of a code taken by a user, the image will likely have some skew(e.g., not have been taken straight-on). The skew can be correctedusing, for example, perspective correction features of OPENCV.

FIGS. 8c and 8d illustrate example deskewed rectangles 308 and 309,respectively, based on the image of FIG. 8b . For example, thestraightened rectangles 308 and 309 are filled with pixels that fetchtheir color information from respective locations in the quadrilateralcandidate in the image. For instance, the perspective quadrilateral 306is transformed into a flat 2D rectangle 309. In another example, if therectangle 308 is filled (e.g., transformed to correct a skew), thepixels can be copied from the lower part of 308 (e.g., corresponding toquadrilateral 306) into rectangle 309. Then the candidate code inrectangle 309 can be analyzed.

FIG. 9 illustrates an example process 900 for analyzing a candidatecode, such as a candidate code identified in the process 700 of FIG. 7.The process 900 will be described in relation to the opticalmachine-readable code 108 in FIG. 10, but need not be so limited. Theoptical machine-readable code 108 can have a minimum offset at the startmarker 401 and at the stop marker 402. The offset can be represented asthe length of a bar as used in optical machine-readable code example204. In other examples, the offset may alternatively be a distance froman invisible center line (herein called axis) 405 to a dot of an opticalcode (e.g., as in the optical code 206) or to a line-contour of anoptical code (e.g., as in the optical code 208), or the distance betweentwo line-contours of a code (e.g., as may be seen in the code 210), or anumber of dots within a rectangular region of a code (e.g., as in code202), or any other optical marks offset from the axis 405.

The process 900 can begin with operation 902, which involves obtaining acandidate optical-machine readable code. The candidate code can beobtained in a variety of ways, including, for example through theprocess 700 described in FIG. 7. In some examples, there may be multiplecandidate codes to be processed. For instance, there may be fourdifferent candidate codes for one image of a code (e.g., obtained fromthe process 700), with each candidate corresponding to a differentrotation of the image.

The process 900 can include operation 904, which involves identifyingmarkers within the code 108. This can involve identifying the locationof the start marker 401 within the start area 404 and the location ofthe stop marker 402 within the stop area 403. In an example, this may bedone by testing for all possible locations within areas 403 and 404 andtesting if there is a region (e.g., disc) of light or darkness at thatpoint. In some examples such a process can involve detecting a knownshape of a marker using a shape detection algorithm, such as one foundin OPENCV. For example, it may be predetermined that the start marker401 and the stop marker 402 may have a circular shape and the markers401, 402 may be detected by identifying circular shapes within theimage. In an example, the markers 401, 402 may be configured to be aparticular horizontal distance x and a particular vertical distance yaway from other features (e.g., other portions of the image area 310),and identifying the markers can be based on the distance.

The process 900 can include operation 906, which involves creating avirtual axis 405. With the location of start marker 401 and stop marker402 established, the virtual axis 405 can be drawn from the start marker401 to the stop marker 402. At a point along the axis (e.g., in themiddle of the axis 405), there may be a reference mark 406 (e.g.,located at the end of a bar to fit in with the visualization of theoptical code 108) representing a maximum offset from the axis 405.

The process 900 can include operation 908, which involves identifyingaxis points. For example, the pixels along axis 405 may be scanned tofind axis points that represent the horizontal position of each verticalbar within the code 108. The vertical bars within the code can have endsrepresenting an optical mark. The axis points can be identified byexamining the alternating patterns of light and dark.

The process 900 can include operation 910, which involves measuring thebars and determining error values for the bars. This can involve, forexample, obtaining the offset. For example, the offset may be theorthogonal distance from the axis 405 (here the length of each bar) ofstart marker 401 and stop marker 402 and the reference mark 406, whichindicates the maximum offset. The offset may then be divided by a stepsize for the possible length values encoded in the bars (e.g., opticalmarks) in the optical code 108. For example, the possible lengths ofbars may vary in steps (e.g., the lengths may be between 3 mm and 30 mmin 3 mm steps) rather than being continuous (e.g., the lengths may beany length between 3 mm and 30 mm). Each bar is then measured in length(e.g., from its respective axis point to the optical mark of the end ofthe bar) and rounded to the nearest step size. An error value(certainty) is encoded based on the difference between the measureddistance and the calculated exact step size. Thus if the length isexactly an integer-multiple of the step size the error value is 0%, ifit is exactly between two step sizes, then the error would be 100%. FIG.11 illustrates an example of determining the error for a bar 1102. Asillustrated, there is a step size s and the end 1104 of the bar 1102 islocated distance D1 from step six and distance D2 from step five. In theillustrated example, because D1 is substantially equal to D2, the erroris 100%.

The process 900 can include operation 912, which involves converting themeasurement of the bars into a code. For example, each measured distanceother than the fixed lengths of the start markers 401, the stop marker402, and the reference mark 406, encodes a number of bits of data (e.g.,at least three bits). The distances are encoded using, for example, aGray code table such that only a single bit changes between each lengthstep. An example of such a table for encoding eight different lengths isshown in TABLE I, below.

TABLE I Line length Bits (abc) 0 000 1 001 2 011 3 010 4 110 5 111 6 1017 100

For example, a line length of five steps would correspond to bits “111”.Advantageously, if an optical mark (e.g., the end of the bar) ismeasured to lie between the distance of steps three and four, only asingle bit is uncertain because only one bit changes between theencodings for steps of three and four (e.g., the possible bits would be:010, which corresponds to three, and 110, which corresponds to four).If, instead of a Gray code, regular binary encoding had been used, allthree bits had been uncertain because all three bits change in theencoding between the binary values of three (011) and four (100). Eachmeasured distance in the above example thus generates three bits withonly one bit being potentially uncertain. Of course, other amount ofbits can be used.

The process can include operation 914, which involves extracting contentfrom the encoded measurements in operation 912. For example, followingoperation 914, there can be a number of bits that have been formed fromthe encoding of the measurements. In some examples, the bits themselvesare usable content. In some examples, the bits are converted into adifferent representation, encoding, or format for use. For instance, thebits can be converted into or otherwise treated as characters, a number,or other kinds of content. As will be further discussed in FIG. 12, thebits may include error detection and error correction information aswell as the desired content of the optical code. The process ofextracting the content can include using the error detection and errorcorrection information to aid in the extraction of the desired content.

FIG. 12 illustrates an example process of encoding content 502 havingerror correcting bits 504 into a 60-bit forward error corrected binarycode word 508. The content 502 can be a series of bits (e.g., 37 bits)that correspond to, for example, a media reference associated with mediacontent item (e.g., a song, artist, or album). The error correcting bits504 can be bits for error correction of the content 502. In theillustrated example, the error correcting bits 504 are Cyclic RedundancyCheck (CRC) error correcting bits. The data 502 and error correctingbits 504 can be combined to form a code 506. The combination process caninvolve shuffling 510 the bits. The code 506 can then be transformedinto an error correcting code 508, such as a forward error correctingcode. The forward error correction used can, for example, be aconvolutional code. In the illustrated example, the code 508 is made upof 60 bits, which can be encoded into 20 offsets/distances (bar lengths)using, for example, the Gray codes of TABLE I.

A shuffling process 510 may be used to spread out potential errors(e.g., if a whole bar/distance is missing). Instead of having theencoded bar lengths (e.g., three bits in the example shown in TABLE I)be consecutive, the lost bits are non-consecutive in the code word. Thisimproves the chances for the forward error correction to work when awhole bar or distance is lost. Thus to scan the optical code, after thelengths of the found bars are converted into bits with certainties, thebits are shuffled back to the right order. The now-ordered bits may befed with the certainties (e.g., bit probabilities or measured potentialerror) into a decoder. In an example, a Viterbi decoder can be used toperform a maximum likelihood decoding of the forward error correctedcode and extract the error corrected bits 506. The error corrected code506 may be decomposed into media reference bits 502 (e.g., 37 bits) andbits 504 (e.g., 8 bits). In some examples, bits 504 can be or include achecksum. The checksum may be verified and, if it is not correct, thequadrilateral candidate may be discarded. Using this process, eventuallya candidate quadrilateral is properly decoded into content, for example,a media reference (e.g., a URL to a location associated with mediacontent or a URI of a media content item).

The content (e.g., media reference used to obtain media content items, aURL, tokens, credentials, or other data) extracted from the optical codecan be used in a variety of ways. FIG. 13 illustrates an example process1300 for a source 1310 to provide content to an image capture device1320 using an optical code. In some examples, the process 1300 can alsoinclude an interaction with a server 1330. The source 1310 is the sourceof the optical code, which is captured using an image capture device1320. In many examples, the source 1310 is a computing device thatprovides the optical code via a display screen. However in otherexamples, for example where the optical code is provided on a printedmedium, the source 1310 can be an organization that generates andpublishes the code. Other configurations are also possible.

The process 1300 can begin with operation 1312, which involves thesource 1310 obtaining an optical code. The way in which the optical codeis obtained can vary depending on the type of content that is to beencoded within the optical code. For example, in some examples, thecontent to be encoded is local to the source 1310. For instance, thesource 1310 can be a smart phone of a person that wants to share a URLor contact information with a friend. In such an example, obtaining theoptical code can involve obtaining the URL or contact information storedlocally at the source 1310 and generating an optical code at the source1310 using one or more techniques described herein.

In some examples, the source 1310 can cooperate with the server 1330 oranother device to obtain the optical code or content for the opticalcode. For example, the source 1310 can be a smart phone of a personwanting to share an album with another person. The identificationinformation of the album (e.g., the URI of the album) may be storedlocally on the source 1310 or in some instances (e.g., where the albumis associated with a streaming provider) the source 1310 may obtain theidentification information of the album from another location, such asthe server 1330.

In some examples, the process 1300 can involve operation 1332, whichinvolves the server processing content to facilitate the source 1310obtaining the optical code. For example, the server 1330 may provide thesource 1310 with content to provide within the optical code. In anotherexample, the server 1330 itself can generate the optical code andprovide it to the source 1310. In still other examples, the server 1330may include a reference table that associates identifiers with content.This can facilitate the sharing of information with an optical code byallowing the source 1310 to provide an optical code with an identifierrather than the content itself. This can provide a variety of benefits.In one example, the use of a reference table can allow for reduced sizeof the content needed to be conveyed by the optical code by allowing arelatively smaller identifier to be associated with a relatively longeritem of content. For example, the optical code may need only contain theidentifier rather than a lengthy piece of content. In another example,this may provide improved security where a user may need to beauthenticated prior to using the reference table to look up the contentto which the identifier refers.

The process 1300 can further include operation 1314, which involvesproviding the optical code. The source 1310 can provide the optical codein a variety of different ways. In some examples, where the source 1310is associated with a display screen (e.g., a computer screen, anelectronic billboard display, or a television screen, among others),providing the optical code can include rendering the optical code at thedisplay screen. In another example, providing the optical code caninvolve causing the optical code to be printed on a physical medium,such as paper, stickers, billboards, boxes, and other physical media. Insome examples, the providing of the optical code can be in response to auser sharing a piece of content, such as a media content item.

In some examples the optical code may be provided in an animated fashionto further strengthen the association with sound waves and music.Animation may be generated by generating distances to marks (e.g., barlengths) by summing a random amount of sine and cosine curves and usinga number of samples (e.g., twenty-three samples) from the summed curveas the distances/offsets for the optical code. In some examples, theanimated curves do not follow the rule of a minimum offset bar in thebeginning and end with a maximum bar in the middle. This speeds updiscarding the animated bar as a candidate image. Another animation maybe generated by creating a linear fade-in of the optical code from leftto right. The code is then initially invisible, then starting from theleft to right, the bars both stretch out from the invisible axis (e.g.,axis 405) into the proper length and at the same time fade from white totheir proper color. After generating enough curves for an animation(e.g., an animation lasting one second), the frames can be stored in asuitable file format, such as a Graphics Interchange Format (GIF),Multiple-image Network Graphics (MNG) format, Portable Network Graphics(PNG) format, and video file formats, among others. After the opticalcode has been displayed for a period of time (e.g., ten seconds), theanimation can be run again.

When the optical code is generated or provided, a color average may bepicked from a region (e.g., area 102 of FIG. 5) by picking colors thatstand out in the image. Picking such colors can involve determiningcolors that have more than a threshold amount of contrast to thebackground by measuring, for example, a brightness value. Brightnessvalues can be determined by, for example, converting the color to itsgrayscale representation (one way of doing so is to convert RGB to YUVand look at the Y value). The chance that image area will be detected asa separate rectangle may thus be increased. In some examples, theoptical code may be inverted. For example, the scanner determines thatthe code is inverted by comparing the color of the code marks to thecode's background color, and if the lines are darker than the tagbackground the code is considered to be inverted.

The process 1300 can further include operation 1322, which involves theimage capture device 1320 capturing the optical code. The image (e.g., atwo-dimensional digital image) can be obtained in a variety of ways,such as by being captured by a camera (e.g., a CCD or CMOS image sensorof an image capture device) or selected from a library of photos. Insome examples, the user can use a particular application to capture theoptical code, such as a software application configured to processoptical codes.

The process 1300 can further include operation 1324, which involvesextracting content from the captured optical code. This operation can beperformed using one or more of the techniques described herein,including but not limited to those techniques described in relation toFIGS. 7 and 9.

In some examples, extracting the content involves identifying an imagearea in the captured digital image, the image area including themachine-readable code. The method also includes, within the image area,finding a predefined optical start marker that defines a start point andfinding a predefined optical stop marker that defines a stop point, andan axis (typically in the form of an imaginary straight line) that isdefined between the start point and the stop point. This can furtherinclude determining multiple axis points along the axis, typicallybetween the start marker and the stop marker. For each axis point, afirst distance within the image area to an optical mark, measured fromthe axis point in a first direction which is orthogonal to the axis, canbe determined. First distances can be translated to a binary code usingGray code. Each first distance may encode at least three bits of thebinary code, the combination of which can correspond to the content.

In some examples, extracting the content from the opticalmachine-readable code further includes finding an optical reference markat an orthogonal distance from the axis, the orthogonal distancedefining a reference distance which the first distances are defined inrelation to. In some embodiments, the reference distance is a maximumdistance. The reference distance may be positioned, as measured in adirection parallel with the axis, in the middle between the start markerand the stop marker. In some embodiments, each of the first distances,as part of the translating, is defined to have any one of a number ofpredefined relative distances relative to the reference distance. Insome embodiments, the difference between the determined first distanceand the nearest predefined relative distances, for each of the axispoints, is used as a measurement of certainty. In some embodiments, themeasurement of certainty is used in a Viterbi decoder. In someembodiments, the start marker and the stop marker may each define aminimum distance to the axis. Thus, the first distances and/or anysecond distances may be measured in relation to the minimum distance tothe axis (e.g., in addition to being measured in relation to thereference distance).

In some embodiments, extracting content further includes, for each axispoint, determining a second distance within the image area to an opticalmark, measured from the axis point in a second direction which isopposite to the first direction (and thus also orthogonal to the axis),and translating the second distances to a binary code using Gray code,each second distance encoding at least three bits of the binary code. Insome embodiments, it is also determined that the binary code of thesecond distances is identical to the binary code of the first distances.By the optical code being symmetrical on both sides of the axis, thecode may be decoded twice, once on each side of the axis, furtherensuring that the decoding is correct. Alternatively, the optical codemay intentionally not be symmetrical with the axis as symmetry axis,allowing a second binary code to be encoded to be encoded by the seconddistances. In some embodiments, the distance between any consecutive twoof the axis points is the same along the axis.

The process 1300 can further include operation 1326, which involvesusing the content extracted from the optical code. How the content isused can vary based on the type of content. For example, the content canbe put into a text field (e.g., where the content is a WI-FI password,the content can be placed into a password field) of an application onthe image capture device 1320, the content can be added to a datastructure (e.g., where the content is contact information), the contentcan be used to take a particular action (e.g., open an application,start or stop music playback, etc.), or access particular content (e.g.,access an album associated with the content), among others.

In some examples, the use of the content can involve cooperation betweenthe image capture device 1320 and the server 1330. Such a process isdescribed in operation 1328, which relates to sending content, andoperation 1334, which relates to processing the sent content at theserver 1330 or another device.

In some examples, the content describes a media reference used to obtainmedia content items in cooperation with the server 1330. The mediareference can be sent to a server 1330 to acquire a media content itemthat corresponds to the media reference. For instance, the mediareference may be a number associated with a media content item. So ascanned media reference can be decoded to yield an index associated witha media content item. To create the media reference, a number (e.g., arandom number) may be allocated on the server 1330 and stored in a tablelinking the number to the desired media content item (e.g., a playlist,an album, a song, a video, a user profile, or an artist profile). Insome examples, the number may be an encrypted consecutively-increasingindex counter can be used. In this manner, the operation 1334 caninvolve determining the desired media content item using the sentcontent and the table. The server 1330 can then take an action basedthereon. For example, the server 1330 can cause the image capture device1320 to play or display the media content item.

A table or another association between codes and content may be usedbecause the content-storing bits of the code (e.g., content 502 of FIG.12) may not be enough on their own to store an arbitrary reference(e.g., a URI to every possible song, playlist, video, user, album andartist). The code can, of course, be extended to have more optical marksto be able to encode any media reference directly. After receiving acode, the server 1330 can return a proper media content item to theimage capture device 1320 that performed the scan. For example, theserver 1330 can cause the image capture device 1320 to play a song ordisplay album associated with the code. If the server 1330 does not finda media reference matching the decoded ID, the server 1330 can respondwith a notification to that effect. In such instances, the flow of theprocess can move back to operation 1324 and repeat the contentextraction, using the processing from the server as feedback. Forexample, the decoding process can use that feedback to know that thecandidate shape or other region in operation 708 was actually anincorrect candidate (e.g., did not decode to valid content). The processof decoding can continue for other candidate shapes until a valid codeis found or until there are no more candidates. The process may continuewithout informing the user of the device 1320 of an invalid code untilthe process is complete.

In an example use case, an optical code can be obtained by a firstdevice from a second device in order to facilitate the association ofthe second device with an account of a user of the first device. As aspecific example, a person may have an account with an audio streamingservice. The person may use the service on a smartphone (e.g., the firstdevice) via an application that the person is logged in to,authenticated with, or otherwise associated with. The person may haverecently purchased a smart speaker (e.g., the second device) and maywant to become associated with the smart speaker with the account (e.g.,associate the smart speaker with an account of the person so the speakercan play audio content using the account). The use of an optical codecan facilitate this and other processes. Examples of such a system andprocess are shown in FIG. 14, and FIG. 15, respectively.

FIG. 14 illustrates an example system 1400 in which a user is using afirst device 1410 to capture an optical code 1424 from a display 1422 ofa second device 1420 to associate the second device 1420 with an accountof the user at a server 1430 connected to the devices 1410, 1420 over anetwork 1425. For example, the user may be logged into a service (e.g.,a streaming audio service) on an application 1412 running on the firstdevice 1410 and may want to associate the second device 1420 with thataccount. Continuing the previous example, the application 1412 may be anaudio streaming service application associated with the user's accountand the user may want to associate the second device 1420 with theaccount. The optical code 1424 can contain information usable in theassociation process.

The first device 1410 can be a computing device configured to facilitatethe capture, processing, and use of an optical code, such as thepreviously-described image capture device 2. In many examples, the firstdevice 1410 will be a smartphone, but the first device 1410 may takeother forms. The second device 1420 can take many different forms. Inthe illustrated example, the device 1420 is a smart speaker systemhaving a display, as well as a processor, memory having executableinstructions to carry out one or more processes described herein, and aninterface for connecting to the server 1430 over the network 1425. Inother examples, the device 1420 may be more or less complex. Additionalfeatures of the system 1400 will be discussed with reference to FIG. 15.The server 130 can be a computing device having a processor, memoryhaving executable instructions to carry out one or more processesdescribed herein, and an interface for connecting to devices over anetwork.

FIG. 15 illustrates an example process 1500 for associating the seconddevice 1420 with an account of a user on a first device 1410 using theoptical code 1424. The process 1500 can include operation 1522, whichinvolves the second device 1420 becoming associated with the server1430. For example, during manufacturing, provisioning, configuration, orinitial setup, the second device 1420 may become known to the server1430. For instance, the server 1430 may include a data structurecontaining known devices (e.g., known device identifiers, IMEI numbers,contact information, IP addresses, etc.). This operation 1522 can alsoinvolve the server 1430 becoming known to the second device 1420. Forexample, the second device 1420 may store information for communicatingwith the server 1430 (e.g., the IP address of the server) in a datastructure in memory. In some examples, second device 1420 may be able toconnect to the server 1430 but may have limited functionality until thedevice 1420 is associated with the user's account.

The process 1500 can include operation 1512, which involves a userassociating the first device 1410 or the application 1412 with anaccount of the user. For example, the user may create an account for aservice associated with the server 1430 (e.g., an audio streamingservice). The user may then associate the account with the device 1410or an application 1412 running thereon. This may involve logging intothe account, obtaining an authentication token, obtaining anauthorization token, or carrying out this process 1500, among others.

The process can include operation 1524, which involves the second device1420 providing an optical code 1424 having an identifier of the device1420. The optical code 1424 may be provided in many different ways. Inthe illustrated example, the code 1424 is provided on the display 1422of the second device 1420. The second device 1420 may provide the code1424 on the display 1422 in response to being powered on, in response toperforming a configuration process, in response to determining it is notassociated with an account (e.g., is not authorized or authenticated),in response to receiving a user input (e.g., via a physical or virtualbutton or other user interface element), or in other situations. Inother examples, the optical code 1424 may be affixed to the device(e.g., via a sticker, label, or printed directly on the device 1420) ormay be provided with materials associated with the device (e.g., aproduct manual, tag, sticker, card, box, or other component associatedwith the device). The device 1420 may prompt the user to scan the codeusing a voice instruction (e.g., as shown in FIG. 14).

The second device 1420 can obtain the code-to-be-provided in a varietyof ways. For example, the second device 1420 may generate the opticalcode itself. In another example, the optical code can be provided withthe second device 1420. For example, the optical code 1424 may begenerated by a device other than the second device 1420 and be stored ina memory of the device 1420 or the code may be provided on material(e.g., manual, box, label, etc.) provided with the second device 1420.In yet another example, the second device 1420 can obtain the opticalcode 1424 (or the content thereof) from the server 1430. For instance,if the second device 1420 is not already associated with an account, thedevice can be configured to connect to the server 1430 (e.g., usinginformation from operation 1522) over the network 1425 and obtain anoptical code for use in associating the device 1420 with an account.

The process 1500 can include operation 1514, which involves capturingthe optical code 1424. In the illustrated example of system 1400, theuser is capturing the optical code 1424 using the application 1412 thatthe user is logged in to on the first device 1410. In other examples,the user may use a default camera app of the device 1410 and send thecaptured image to another device for processing.

The process 1500 can include operation 1516, which involves extractingcontent from the captured optical code 1424. In the example system 1400,this is performed on the first device 1410 to obtain the identifier ofthe second device 1420 encoded in the optical code 1424. In someexamples, this can involve the first device 1410 executing anapplication configured to perform the steps of FIGS. 7 and 9. In someexamples, the content of the optical code 1424 can itself be anauthorization token, an authentication token, or other content thatallows the user or the device 1410 to control the device 1420 (e.g.,directly or over the server 1430).

The process 1500 can include operation 1518, which involves sending theidentifier obtained from the optical code 1424 to the server 1430 overthe network 1425. The sending can be performed from the application 1412that the user is logged in to or in other ways. Along with theidentifier, user-specific information can be sent to the server 1430that allows the server to associate the device identifier with theuser's account. For example, the message that includes the deviceidentifier can also include a user account identifier (e.g., a user ID).

The process 1500 can include operation 1532, which involves the server1430 receiving the information sent from the first device 1410 andmatching the identifier with the second device 1420. The server 1430 canuse the device identifier to identify the second device 1420 in avariety of ways. This operation 1532 can involve the server 1430determining how to contact the second device 1420, such as the correctaddress (e.g., IP address) and protocols to use to contact the seconddevice 1420. In some examples, the identifier itself contains sufficientinformation to contact the device 1420. In other examples, the server1430 can use the identifier to obtain the information. For example, theserver 1430 can use the identifier to look up contact information in adata structure established in operation 1522. This operation 1532 canfurther involve associating the second device 1420 with the user'saccount. For instance, the association can involve registering thedevice 1420 at the server as associated with the user's account,granting the device 1420 permission to take actions associated with theuser's account, and logging the user in to the device, among others. Forexample, the association can involve updating a data structure stored atthe server 1430 to include the relevant information.

The process 1500 can include operation 1534, which involves the server1430 sending a token for the user's account to the second device 1420using the contact information obtained in operation 1532 and the accountinformation. The operation 1530 can involve sending an authenticationtoken (e.g., an OPENID token) to the device 1420, sending anauthorization token (e.g., an OAUTH token) to the device 1420, or takingother actions.

The process 1500 can include operation 1526, which involves the seconddevice 1420 receiving the token sent by the server 1430.

The process 1500 can include operation 1528, which involves the seconddevice 1420 using the token to access services associated with theuser's account. For example, the second device 1420 may use the tokenwith API requests to the server 1430 in order to access services onbehalf of the user's account. For example, where the account is anaccount associated with a streaming audio service and the second device1420 is a smart speaker, this can involve the second device 1420obtaining streaming audio content from the server 1430 that isassociated with the user's account. In some examples, this can alsoinvolve the user controlling the second device 1420 with the firstdevice 1410.

The present disclosure has mainly been described above with reference toparticular embodiments. However, as is readily appreciated by a personskilled in the art, other embodiments than the ones disclosed above areequally possible within the scope of the present disclosure, as definedby the appended claims. The various embodiments described above areprovided by way of illustration only and should not be construed tolimit the claims attached hereto. Those skilled in the art will readilyrecognize various modifications and changes that may be made withoutfollowing the example embodiments and applications illustrated anddescribed herein, and without departing from the true spirit and scopeof the following claims.

What is claimed is:
 1. A method of reading an optical machine-readablecode using an image capture device, the method comprising: capturing animage with an image sensor of an image capture device; identifying animage area in the captured image, the image area having amachine-readable code; within the image area, finding a predefined startmarker defining a start point and finding a predefined stop markerdefining a stop point, wherein an axis is defined between the startpoint and the stop point; defining a plurality of axis points along theaxis; for each axis point of the plurality of axis points, determining afirst distance within the image area to a mark, the first distancemeasured from the axis point in a first direction which is orthogonal tothe axis; and translating the first distances to a binary code of atleast three bits using Gray code.
 2. The method of claim 1, furthercomprising: finding a reference mark at an orthogonal distance from theaxis, the orthogonal distance defining a reference distance that thefirst distances are defined in relation to.
 3. The method of claim 2,wherein the reference distance is a maximum distance.
 4. The method ofclaim 2, wherein the reference mark is, in a direction parallel with theaxis, positioned in a middle between the start marker and the stopmarker.
 5. The method of claim 2, wherein each of the first distances,as part of the translating, is defined to have any one of a number ofpredefined relative distances relative to the reference distance.
 6. Themethod of claim 5, wherein, for each of the plurality axis points, adifference between the determined first distance and a nearestpredefined relative distance is used as a measurement of certainty. 7.The method of claim 6, further comprising using the measurement ofcertainty in a Viterbi decoder.
 8. The method of claim 1, wherein thestart marker and the stop marker each define a minimum distance to theaxis.
 9. The method of claim 1, further comprising: for each axis pointof the plurality of axis points, determining a second distance withinthe image area to a mark, measured from the axis point in a seconddirection which is opposite to the first direction; and translating thesecond distances to a binary code using Gray code, each second distanceencoding at least three bits of the binary code.
 10. The method of claim9, further comprising: determining that the binary code of the seconddistances is identical to the binary code of the first distances. 11.The method of claim 1, wherein a distance between any consecutive twoaxes points of the plurality of axis points is the same along the axis.12. A non-transitory computer readable medium comprising instructionsexecutable by a processor to perform a method comprising: capturing animage using an image sensor of an image capture device; identifying animage area in the captured image, the image area including amachine-readable code; within the image area, finding a predefined startmarker defining a start point and find a predefined stop marker defininga stop point, an axis being defined between the start point and the stoppoint; defining a plurality of axis points along the axis; for each axispoint, determining a first distance within the image area to a mark,measured from the axis point in a first direction which is orthogonal tothe axis; and translating the first distances to a code.
 13. Thenon-transitory computer readable medium of claim 12, wherein the imagecapture device is a smartphone comprising a camera.
 14. Thenon-transitory computer readable medium of claim 12, wherein translatingthe first distances to the code comprises: translating the firstdistances to a binary code using Gray code, wherein each first distanceof the plurality of plurality of axis points translates to at leastthree bits of the binary code; and wherein the method further comprisesusing, as a measurement of certainty in a Viterbi decoder, a differencebetween the determined first distance and a nearest predefined relativedistance for each of the axis points
 15. The non-transitory computerreadable medium of claim 12, wherein the method further comprises usingcontent within the code to associate a device with an account by:extracting an identifier of the device from the code; and sending theidentifier and account information to a server.
 16. A method forgenerating a machine-readable code, the method comprising: obtainingdata; translating the data into mark distances within an image area,each of the mark distances being measured from an axis point on an axisin the image area, in a direction orthogonal to the axis; forming a markat the end of each of the mark distances in the image area; forming astart marker at a first end of the axis, wherein the start markerdefines a start point; forming a stop marker at a second end of theaxis, wherein the stop marker defines a stop point; and providing theimage area.
 17. The method of claim 16, wherein providing the image areacomprises: presenting an image comprising the image area on an displaywhereby the marks form a machine-readable code in the image area in theimage.
 18. The method of claim 17, further comprising: determining abrightness of a region of the image; and selecting a color for the markshaving greater than a threshold amount of contrast compared to thedetermined brightness.
 19. The method of claim 16, further comprising:animating the image area, wherein providing the image area comprisesproviding the animated image area.
 20. The method of claim 16, whereinthe data comprises a binary code, and wherein translating the data intomark distances comprises translating the binary code into mark distancesusing Gray code.
 21. An image capture device for reading an opticalmachine-readable code, the image capture device comprising: processingcircuitry; and storage storing instructions executable by the processingcircuitry whereby the image capture device is operative to: capture adigital image using an image sensor of the image capture device;identify an image area in the captured digital image, the image areahaving the optical machine-readable code; within the image area, find apredefined optical start marker defining a start point and find apredefined optical stop marker defining a stop point, an axis beingdefined between the start point and the stop point; define a pluralityof axis points along the axis; for each axis point, determine a firstdistance within the image area to an optical mark of themachine-readable code, measured from said axis point in a firstdirection which is orthogonal to the axis; and translate the firstdistances to a binary code by using Gray code, each first distanceencoding at least three bits of the binary code.
 22. The image capturedevice of claim 21, wherein the image capture device is a smartphonehaving a digital camera.